logictest: only run create_as_non_metamorphic under local

This test is very expensive because it was writing 100Mib of data. It now
writes more like 5. Nevertheless, let's not run it in so many places. I
did verify that it still tests what it was intended to test.

Fixes #91080

Release note: None

pkg/sql/logictest/testdata/logic_test/create_as_non_metamorphic

@@ -1,15 +1,15 @@
-# LogicTest: !metamorphic-batch-sizes
+# LogicTest: !metamorphic-batch-sizes local
 # Disabled to allow us to validate create as with large batch sizes.
 
 # Regression test for #81554, where tried to do gigantic batches for CTAS in
 # explicit transactions. Use a fixed command size, so that an error is decoupled
 # fom the default size.
 statement ok
-SET CLUSTER SETTING kv.raft.command.max_size='5m'
+SET CLUSTER SETTING kv.raft.command.max_size='4.01MiB'
 
 statement ok
 BEGIN;
-CREATE TABLE source_tbl_huge AS SELECT 1::CHAR(256) FROM generate_series(1, 500000);
+CREATE TABLE source_tbl_huge AS SELECT 1::CHAR(256) FROM generate_series(1, 50000);
 COMMIT;
 
 statement ok